Bone Tumors Practice Questions

Q: An 8-year-old boy presents with a swelling in the mid-thigh region. On examination, femoral thickening was found with Codman's triangle. On aspiration, greyish-white liquid was aspirated that showed atypical round cells with MIC-2 positivity. What is the most likely diagnosis?

Ewing's sarcoma. **Explanation:** The clinical presentation and immunohistochemistry point definitively to **Ewing’s Sarcoma**. 1. **Why Ewing’s Sarcoma is correct:** * **Age & Location:** It typically affects children and adolescents (5–15 years) and is the most common tumor of the **diaphysis** (mid-shaft) of long bones. * **Radiology:** While "onion-skin" appearance is classic, Ewing’s is highly aggressive and can present with a **Codman’s triangle** (periosteal elevation), indicating a rapidly growing lesion. * **Pathology:** The aspiration of "greyish-white liquid" (often mistaken for pus) containing **small round blue cells** is characteristic. * **Immunohistochemistry (IHC):** **MIC-2 (CD99)** positivity is the most specific marker for the Ewing’s family of tumors. 2. **Why other options are incorrect:** * **Osteosarcoma:** Usually occurs in the **metaphysis** (not mid-thigh/diaphysis). While it shows Codman’s triangle, IHC would show Osteocalcin positivity, not MIC-2. * **Pyogenic/Tubercular Osteomyelitis:** These can mimic Ewing’s clinically (fever, swelling) and radiologically. However, the presence of **atypical round cells** and **MIC-2 positivity** confirms a neoplastic process rather than an infection. **High-Yield Clinical Pearls for NEET-PG:** * **Translocation:** Associated with **t(11;22)** involving the EWS-FLI1 gene. * **PAS Stain:** Ewing’s cells are **PAS positive** due to cytoplasmic glycogen (unlike Lymphoma). * **Mimicry:** It is known as the "Great Mimicker" because it often presents with systemic symptoms like fever and elevated ESR, resembling osteomyelitis. * **Treatment:** It is highly radiosensitive; the standard protocol is Neoadjuvant Chemotherapy (VACA regimen) followed by surgery/radiotherapy.

Q: Which of the following conditions is a risk factor for the development of osteosarcoma?

Paget's disease. ### Explanation **Correct Option: C. Paget’s Disease** **Why Paget’s Disease is the Correct Answer:** Paget’s disease of the bone (Osteitis deformans) is characterized by high bone turnover with disorganized bone remodeling. In approximately 1% of cases (higher in polyostotic disease), this rapid cellular proliferation leads to malignant transformation, most commonly into **Secondary Osteosarcoma**. This typically occurs in elderly patients (60–70 years), creating a "bimodal distribution" for osteosarcoma (the first peak being in adolescents). **Why Other Options are Incorrect:** * **A. Osteoid Osteoma:** This is a benign, small (less than 2 cm), bone-forming tumor characterized by a radiolucent nidus. It has **no malignant potential** and does not progress to osteosarcoma. * **B. Osteoblastoma:** Often considered a "giant osteoid osteoma" (greater than 2 cm), it is also a benign lesion. While it can be locally aggressive, it is not a precursor to osteosarcoma. * **D. All of the above:** Since Osteoid osteoma and Osteoblastoma are strictly benign, this option is incorrect. **NEET-PG High-Yield Clinical Pearls:** * **Secondary Osteosarcoma Risk Factors:** Apart from Paget’s disease, other risk factors include prior **Radiation therapy** (most common cause of secondary OS), Li-Fraumeni syndrome (p53 mutation), Hereditary Retinoblastoma (RB1 mutation), and Rothmund-Thomson syndrome. * **Radiology:** Look for the "Sunray appearance" or "Codman’s triangle" on X-ray. * **Pagetoid Osteosarcoma:** Suspect this in an elderly patient with known Paget’s disease who presents with a sudden increase in pain, a new soft tissue mass, or a pathological fracture. * **Lab Marker:** Alkaline Phosphatase (ALP) is significantly elevated in both Paget’s disease and Osteosarcoma.

Q: Mirel's criteria is developed for the evaluation of?

Risk of pathological fracture. **Explanation:** **Mirel’s Scoring System** is a validated clinical tool used to quantify the **risk of pathological fracture** in patients with long bone metastases. It helps orthopedic surgeons decide between prophylactic internal fixation and non-operative management (like radiotherapy). The score is based on four parameters, each scored from 1 to 3: 1. **Site:** Upper limb (1), Lower limb (2), Peritrochanteric (3). 2. **Pain:** Mild (1), Moderate (2), Functional/Aggravated by weight-bearing (3). 3. **Lesion Type:** Blastic (1), Mixed (2), Lytic (3). 4. **Size (relative to bone diameter):** 2/3 (3). **Interpretation:** * **Score ≤ 7:** Low risk; manage conservatively. * **Score ≥ 9:** High risk (>33%); **prophylactic fixation** is indicated. * **Score of 8:** Borderline; clinical judgment is required. **Analysis of Incorrect Options:** * **A. Fatigue fracture:** These are stress fractures in normal bone due to repetitive abnormal loading (e.g., March fracture). Mirel’s specifically addresses diseased bone. * **B. Severity of osteoporosis:** This is assessed using the **T-score** via DEXA scan or the Singh’s Index (on X-ray). * **D. Neurological deficit:** This is typically graded using the **Frankel** or **ASIA scale** (for spinal cord injuries). **High-Yield Pearls for NEET-PG:** * **Most common site** of skeletal metastasis: **Spine**. * **Most common source** of bone metastasis: **Breast** (females), **Prostate** (males). * **Lytic vs. Blastic:** Kidney and Thyroid cancers are classically purely lytic; Prostate is classically blastic. * **Prophylactic Fixation:** Always preferred over fixing a completed fracture because it allows faster mobilization and has fewer complications.

Q: A 30-year-old woman complains of left knee joint pain that has increased after exercise for the past 4 months. An X-ray shows an eccentric bone cyst. What is the likely diagnosis?

Aneurysmal bone cyst. **Explanation:** The diagnosis of **Aneurysmal Bone Cyst (ABC)** is based on the patient's age and the characteristic radiological finding of an **eccentric** lesion. 1. **Why A is correct:** ABC is a benign but locally aggressive vascular lesion. It typically occurs in the metaphysis of long bones (like the femur or tibia around the knee). Radiologically, it presents as an **eccentric, "blow-out" expansile osteolytic lesion** that thins the cortex. It is common in the second and third decades of life (20s–30s). 2. **Why B is incorrect:** A **Unicameral Bone Cyst (UBC)** or Simple Bone Cyst is typically **centrally located** within the medullary cavity, not eccentric. It most commonly affects children (5–15 years) and is often found in the proximal humerus or femur. 3. **Why C is incorrect:** Hydatid cysts of the bone are rare and usually present as multiple, multiloculated "bunch of grapes" lucencies without a periosteal reaction, typically in the spine or pelvis. 4. **Why D is incorrect:** Fibrous dysplasia presents with a characteristic **"Ground Glass" appearance** on X-ray and is usually centrally located with a "rind" of sclerotic bone. **High-Yield NEET-PG Pearls:** * **ABC Hallmark:** MRI shows **"Fluid-fluid levels"** due to the settling of RBCs within the blood-filled cavernous spaces. * **Location Rule:** If the lesion is eccentric and involves the **epiphysis** in a skeletally mature patient, think **Giant Cell Tumor (GCT)**. If it is eccentric and **metaphyseal**, think **ABC**. * **Treatment:** Curettage and bone grafting is the standard treatment for ABC.

Q: An eight-year-old boy presents with progressive swelling around the knee joint of two months' duration following mild trauma. Local examination reveals an irregular bony swelling over the upper end of the tibia, with raised local temperature and variable consistency and ill-defined margins. What is the most likely diagnosis?

Osteogenic sarcoma. **Explanation:** The clinical presentation strongly points towards **Osteogenic Sarcoma (Osteosarcoma)**, the most common primary malignant bone tumor in children and adolescents. **1. Why Osteogenic Sarcoma is correct:** * **Age & Site:** It typically occurs in the second decade of life (8–25 years) and most commonly affects the **metaphysis** of long bones around the knee (distal femur or proximal tibia). * **Clinical Features:** Rapidly progressive swelling, often triggered by a history of minor trauma (which draws attention to the pre-existing lesion). * **Examination Findings:** The presence of **raised local temperature** (due to high vascularity), variable consistency (areas of bone formation vs. necrosis), and **ill-defined margins** are classic hallmarks of a highly aggressive, malignant bone tumor like osteosarcoma. **2. Why other options are incorrect:** * **Giant Cell Tumor (GCT):** Typically occurs in a slightly older age group (20–40 years) and is **epiphyseal** in location. It is usually "locally aggressive" but lacks the systemic inflammatory signs like raised temperature seen here. * **Ewing’s Sarcoma:** While it also presents with pain and swelling in children, it usually involves the **diaphysis** (shaft) of long bones and often presents with systemic symptoms like fever and elevated ESR, mimicking osteomyelitis. * **Secondary Metastasis:** Rare in an 8-year-old. When present in children, they usually arise from Neuroblastoma or Wilms’ tumor and are rarely isolated bony swellings at the tibia. **Clinical Pearls for NEET-PG:** * **Radiology:** Look for "Sunray spiculation" (periosteal reaction) and "Codman’s triangle." * **Laboratory:** Characteristically shows elevated **Serum Alkaline Phosphatase (ALP)** levels, which correlate with osteoblastic activity and prognosis. * **Gold Standard Investigation:** Biopsy. * **Most common site of metastasis:** Lungs (via hematogenous spread).

Q: Which of the following bone tumors characteristically responds to aspirin?

Osteoid osteoma. **Explanation:** **Osteoid Osteoma** is a benign, bone-forming tumor characterized by a small radiolucent core called a **nidus** (less than 2 cm). The hallmark clinical feature is **nocturnal pain** that is dramatically relieved by **aspirin** or other NSAIDs. This response occurs because the nidus contains high concentrations of **prostaglandins** (specifically PGE2 and PGI2), which are potent mediators of pain and inflammation. Aspirin inhibits cyclooxygenase (COX) enzymes, thereby blocking prostaglandin synthesis and providing rapid symptomatic relief. **Analysis of Incorrect Options:** * **Osteoma:** A benign, slow-growing lesion of cortical bone (common in the skull/paranasal sinuses) that is usually asymptomatic and does not produce prostaglandins. * **Osteoblastoma:** Often called "giant osteoid osteoma" (nidus >2 cm), it is histologically similar but lacks the characteristic nocturnal pain and does **not** respond consistently to aspirin. * **Osteoclastoma (Giant Cell Tumor):** An aggressive tumor occurring at the epiphysis. Pain is due to local destruction and expansion, not prostaglandin-mediated pathways, and thus does not respond specifically to aspirin. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** A young male (10–20 years) with aching pain in the femur or tibia that worsens at night. * **Radiology:** Shows a small radiolucent **nidus** surrounded by dense **perifocal reactive sclerosis**. * **Gold Standard Investigation:** CT scan (best to visualize the nidus). * **Treatment of Choice:** Radiofrequency ablation (RFA) or surgical excision of the nidus.

Q: Soap bubble appearance on the distal end of the radius is diagnostic of which of the following?

Osteoclastoma. **Explanation:** **Osteoclastoma (Giant Cell Tumor - GCT)** is the correct answer because it characteristically presents as a **"soap bubble"** appearance on X-ray. This appearance is caused by the tumor’s eccentric, expansile growth which thins the overlying cortex and creates internal trabeculations. * **Why it is correct:** GCT is a benign but locally aggressive tumor that typically occurs in the **epiphysis** of long bones after the growth plate has closed (ages 20–40). The **distal radius** and the **distal femur/proximal tibia** (around the knee) are the most common sites. Its hallmark features are an eccentric location and the subarticular extension (reaching the joint surface). **Why other options are incorrect:** * **A. Osteoblastoma:** Typically involves the posterior elements of the spine. It presents as a well-circumscribed radiolucent lesion, often larger than 2 cm, but lacks the classic soap-bubble expansion seen in GCT. * **C. Osteosarcoma:** A highly malignant tumor characterized by a **"Sunburst appearance"** or **"Codman’s triangle"** due to aggressive periosteal reaction. It usually occurs in the metaphysis of young adolescents. * **D. Ewing’s Sarcoma:** Characterized by an **"Onion-skin appearance"** (lamellated periosteal reaction). It typically affects the diaphysis of long bones in children. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** GCT is the only tumor that is primarily **Epiphyseal**. * **Histology:** Shows characteristic multinucleated giant cells (osteoclast-like) scattered among mononuclear stromal cells (the actual neoplastic cells). * **Treatment:** Intralesional curettage with the use of a bone graft or bone cement (adjuvant therapy like liquid nitrogen or phenol is often used to reduce recurrence). * **Denosumab:** A monoclonal antibody against RANKL used in unresectable or recurrent GCT.

Q: Which of the following is typically associated with osteoblastic secondaries in the spine?

Carcinoma prostate. **Explanation:** The spine is the most common site for skeletal metastasis. Metastatic bone lesions are classified as **osteolytic** (bone destruction), **osteoblastic** (bone formation), or **mixed**, depending on the interaction between tumor cells and the bone microenvironment. **1. Why Carcinoma Prostate is Correct:** Prostate cancer cells secrete factors like **Bone Morphogenetic Proteins (BMPs)**, Wnt proteins, and Endothelin-1, which directly stimulate **osteoblasts**. This leads to the deposition of dense, irregular new bone, appearing radiographically as "ivory vertebrae" or radio-opaque spots. It is the classic example of purely osteoblastic secondaries in males. **2. Why the Other Options are Incorrect:** * **Carcinoma Thyroid:** Typically produces highly vascular, **purely osteolytic** (bone-destroying) lesions. These are often "expansile" or "pulsatile" in nature. * **Endometrial Carcinoma:** While it can metastasize to bone, it is rare compared to other gynecological cancers and usually presents as osteolytic lesions. * **Carcinoma Rectum:** Most gastrointestinal malignancies (colon, rectum, stomach) produce **osteolytic** lesions when they spread to the skeleton. **High-Yield Clinical Pearls for NEET-PG:** * **Most common source of Osteoblastic secondaries:** Prostate (Males), Breast (Females - though breast is often mixed). * **Most common source of Osteolytic secondaries:** Lung cancer (Males), Breast cancer (Females), Kidney (RCC), and Thyroid. * **Batson’s Plexus:** The valveless vertebral venous plexus that allows retrograde spread of prostate cancer to the spine without passing through the lungs. * **Investigation of Choice:** **MRI** is the most sensitive for early detection; **Bone Scan (Technetium-99m)** identifies osteoblastic activity (but may be negative in purely lytic lesions like Multiple Myeloma).

Q: What is the most common cause of punched-out lesions in the phalanges?

Enchondroma. ### Explanation **Correct Answer: A. Enchondroma** **Why Enchondroma is correct:** Enchondroma is the **most common primary bone tumor of the hand** (specifically the phalanges and metacarpals). It is a benign, hyaline cartilage-forming tumor that arises within the medullary cavity. On X-ray, it typically presents as a well-defined, **"punched-out" lytic lesion** or a geographic area of rarefaction. While it may show "popcorn calcification" (stippled calcification) in long bones, in the small bones of the hand, it often appears purely lytic and can cause thinning or endosteal scalloping of the cortex. **Why the other options are incorrect:** * **B. Chondrosarcoma:** While this is a malignant cartilage tumor, it is rare in the small bones of the hand. It usually affects the axial skeleton (pelvis, femur). If found in the hand, it is often a malignant transformation of a pre-existing enchondroma. * **C. Aneurysmal Bone Cyst (ABC):** ABCs are characterized by an "expansile," soap-bubble appearance rather than a simple punched-out lesion. They typically affect the metaphysis of long bones and are associated with fluid-fluid levels on MRI. * **D. Multiple Myeloma:** This is the most common cause of "punched-out" lesions in the **skull and axial skeleton** in elderly patients. However, it rarely involves the distal bones (phalanges). **High-Yield Clinical Pearls for NEET-PG:** * **Ollier Disease:** Multiple enchondromatosis. * **Maffucci Syndrome:** Multiple enchondromas + Soft tissue hemangiomas (higher risk of malignancy). * **Pathological Fracture:** The most common clinical presentation of a phalangeal enchondroma. * **Radiological Sign:** "Endosteal scalloping" is a classic feature. * **Treatment:** Usually asymptomatic; if symptomatic or at risk of fracture, **Curettage and Bone Grafting** is the treatment of choice.

Question 1

Arrange the following tumours according to increasing age group: Ewing's Sarcoma, Osteosarcoma, Osteoclastoma, Chondrosarcoma?

Accepted Answer

Ewing's Sarcoma, Osteosarcoma, Osteoclastoma, Chondrosarcoma

Answer

Osteosarcoma, Chondrosarcoma, Ewing's Sarcoma, Osteoclastoma

Answer

Osteoclastoma, Osteosarcoma, Chondrosarcoma, Ewing's Sarcoma

Answer

Chondrosarcoma, Ewing's Sarcoma, Osteoclastoma, Osteosarcoma

Question 2

An 8-year-old boy presents with a swelling in the mid-thigh region. On examination, femoral thickening was found with Codman's triangle. On aspiration, greyish-white liquid was aspirated that showed atypical round cells with MIC-2 positivity. What is the most likely diagnosis?

Accepted Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Tubercular osteomyelitis

Answer

Pyogenic osteomyelitis

Question 3

Which of the following conditions is a risk factor for the development of osteosarcoma?

Accepted Answer

Paget's disease

Answer

Osteoid osteoma

Answer

Osteoblastoma

Answer

All of the above

Question 4

Mirel's criteria is developed for the evaluation of?

Accepted Answer

Risk of pathological fracture

Answer

Risk of fatigue fracture

Answer

Severity of osteoporosis

Answer

Severity of neurological deficit

Question 5

A 30-year-old woman complains of left knee joint pain that has increased after exercise for the past 4 months. An X-ray shows an eccentric bone cyst. What is the likely diagnosis?

Accepted Answer

Aneurysmal bone cyst

Answer

Unicameral bone cyst

Answer

Hydatid cyst

Answer

Fibrous dysplasia

Question 6

An eight-year-old boy presents with progressive swelling around the knee joint of two months' duration following mild trauma. Local examination reveals an irregular bony swelling over the upper end of the tibia, with raised local temperature and variable consistency and ill-defined margins. What is the most likely diagnosis?

Accepted Answer

Osteogenic sarcoma

Answer

Giant cell tumor

Answer

Ewing's sarcoma

Answer

Secondary metastasis

Question 7

Which of the following bone tumors characteristically responds to aspirin?

Accepted Answer

Osteoid osteoma

Answer

Osteoma

Answer

Osteoblastoma

Answer

Osteoclastoma

Question 8

Soap bubble appearance on the distal end of the radius is diagnostic of which of the following?

Accepted Answer

Osteoclastoma

Answer

Osteoblastoma

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Question 9

Which of the following is typically associated with osteoblastic secondaries in the spine?

Accepted Answer

Carcinoma prostate

Answer

Carcinoma thyroid

Answer

Endometrial carcinoma

Answer

Carcinoma rectum

Question 10

What is the most common cause of punched-out lesions in the phalanges?

Accepted Answer

Enchondroma

Answer

Chondrosarcoma

Answer

Aneurysmal bone cyst

Answer

Multiple myeloma

Bone Tumors — MCQs

Bone Tumors — MCQs

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